1. Field of the Invention
The present invention relates to a semiconductor device and a method of mounting the same and, more particularly, to the configuration of a lead of a semiconductor device and a method of mounting the semiconductor device having the lead of such a configuration.
2. Description of the Background Art
FIG. 1 is a partially cutaway perspective view showing a conventional DIL (Dual In Line Package) type semiconductor device which has leads arranged in parallel and extending downward from opposite sides of a package. Referring to FIG. 1, this DIL type semiconductor device 1a comprises a semiconductor element 2 fixed on a die pad 3 for supporting the semiconductor element 2 by means of solder material 4. The semiconductor element 2 has electrodes (not shown) which are connected with leads 5 through thin metal wires 6. Portions of the leads 5 to be connected with the wires 6 are provided with plating such as Ag plating in order to ensure the connection. The semiconductor element 2 and the wires 6 are sealed with mold resin 7 which forms a plastic package for protection against external forces. After the completion of the package 7, the leads 5 are cut away from a lead frame (not shown) and ends 5a of the leads 5 projecting from the package 7 are bent perpendicularly to the package 7.
FIG. 2B is a front view showing the DIL type semiconductor device 1a mounted on a printed circuit board 8. FIG. 2C is a side view of FIG. 2B and FIG. 2A is a fragmentary enlarged view of FIG. 2B. The leads 5 are inserted into through holes 11 of the board 8 from the upper side of the board 8, and then solder 10 is supplied in the through holes 11 from the lower side of the board 8 to connect the leads 5 with leads 9. Thus the semiconductor device 1a is mounted on the board 8. The leads 9 are connected with other devices and the like (not shown) mounted on the board 8 through a wiring pattern (not shown) formed on the board 8.
FIG. 3 is a partially cutaway perspective view showing a conventional ZIL (Zigzag In Line Package) type semiconductor device which has leads extending from one side of a package which are bent alternately on two planes in a zigzag manner. This ZIL type semiconductor device 1b is mounted on a printed circuit board 8 as shown in FIG. 4, wherein FIG. 4B is a front view, FIG. 4C is a side view of FIG. 4B and FIG. 4A is a fragmentary enlarged view of FIG. 4B. Reference numerals 2 to 11 in FIG. 3 and FIG. 4 denote the same components as in FIG. 1 and FIG. 2.
The DIL type semiconductor device shown in FIG. 1 and the ZIL type semiconductor device shown in FIG. 3 are called through hole devices because these devices are mounted on the board 8 by inserting the leads 5 into the through holes 11.
FIG. 5 is a partially cutaway perspective view showing a conventional SOP (Small Outline Package) type semiconductor device which has steplike leads arranged in parallel which are extending from opposite sides of a package. This SOP type semiconductor device 1c is mounted on a printed circuit board 8 as shown in FIG. 6, wherein FIG. 6B is a front view, FIG. 6C is a side view of FIG. 6B and FIG. 6A is a fragmentary enlarged view of FIG. 6C. Reference numerals 2 to 10 in FIG. 5 and FIG. 6 denote the same components as in FIG. 1 to FIG. 4.
The SOP type semiconductor device shown in FIG. 5 is called a surface mounting type device (SMD) because this device is mounted on the board 8 without through holes.
Disadvantageously, the conventional semiconductor devices structured as hereinbefore described can not be mounted across a plurality of printed circuit boards not lying on the same plane.